paul_holloway1988

GWR Null Values

Discussion created by paul_holloway1988 on May 3, 2012
I'm currently trying to run some GWR analyses in ArcGIS 10.0. I have four environmental variables for my dependant variable (species richness).
The relationships I'm running are not necessarily linear, so I have created second order polynomials to explain the variance for two of the environmental variables. This clears up a lot of the explained variance in OLS and GWR when all the variables are combined. However, I want to look at how the R2 and coefficients change for each of the individual variables at a very local scale. Three of the GWR and environmental variables work fine, but for temperature (second order polynomial) at a fine resolution, many of the cells contain null (or infinity) values.

I have read several discussion topics on this, which highlight the issue of multicollinearity in the environmental dataset. I get this, and the data does appear to perhaps be locally clustered. From reading these discussions, the two methods suggested to overcome this by creating new variables 1) mean - variable value 2) create a new range variable, have not solved my issue.

I was wondering if anyone had any advice on how to overcome this issue?

Cheers
Paul

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